Basically when fired up from cold, the entire system keeps shutting down after 10 mins with ignition lock out LED coming on. Then when I press the reset button and run the tap or heating, it fires up for about 10 seconds, then shuts down again. I have on recommendation had the diverter valve replaced and put in a new PC board after a second recommendation. It is still doing the same thing. During the period before it shuts down, I can hear the ignition clicking, even though the it's fired up. Any ideas? Thanks